Telephone system.



No.- 858,454 PATENTED JULY 2, 1907.

E. B. HBAFORD. j TELEPHONE SYSTEM.

APPLICATION PILED'DBO. 31, 1906.

2 SHEETS-SHEET 1.

-6 A YTORNE M9 E. B.- HEAFORD.

" TELEPHONE SYSTEM. 7

APPLICATION FILED DEG- 31.1906.

PATENTED JULY 2, 1907.

2 SHEETS-SHEETZ.

ATTORNE S U NITED STATES EDWIN "BOWEN nmi om), or OMAHA, Nannie/ Ki;

. TELEPHONE SYSTEM.

lo all whom it may concern:

Be it known that L'EDWN BOWEN HEAFORD, a citizen of the United States, residing at Omaha, in the county of Douglas and State of Nebraska, have iiivented new and useful Telephone System, of which the following is a specification.

This invention relates to improvei'nents'in comrrion battery telephone systems of theImulti'ple type and it relates more particularly to improvements whereby a cord circuit may be employed having only two wires,

' as distinguished from the usual three wire circuit and the accompanying complicated apparatus at theswitch .llUliltl. i I

The invention has or one of its objects to improve amlsiniplify switch board circuits of the character re- .-1(."Cl to, so as to be comparatively inexpensive andio construct, thoroughly reliable and eflicientin servimi: and designed to eliminate certain of the compile-v1 ions at the switch board. c I i A further object of the invention-is the prov ision'jof a two wire cord circuit adapted to be used'inronnection with line circuits having improved line r'elays'for the signal and improved arrangement of the cut-out relays.

Withtheseol jeets in view, and others as-will appear as-t-he nature of the intention is better understood, the invention comprises the various novel -features of construction and arrangement of parts, which will be more fully described hereinafter and set forth with particularity in the claims appended heretof Inthe accompanying drawings, which illustrate cer tai'n of the embodiments of the invention, Figure 1 is a diagrammatic view of a portion of a telephonecircuit showing the yarious apparatus in normal condition Fig. 2 is a similar view showing the system in 7 condition for conversation between subscribers. u

"Corresponding parts in the several figures-are indir rated throughout by similar characters of reference.

Inthe present instance, I have elected to illustrate only those p'ortions'of the cord and switchboard circuits whichare necessary to an understanding of the invention, hence only onesuhscribers line with itsnecessary apparatus at the switch board and only onehalf of the cord circuit have been shown, the usual listening and ringing keys and cord plug at the opposite end of the cord circuithaving been eliminated since these are of the usual-character employed in standard multiple switch boardsq Referringito the drawings, subscribers stations of the telephone system and B the central exchange, each having respectivelya line-cirsuit l and'Z cord circuit 3 and 4.. The apparatus at th. subscribers station may be of any app roved house volition. At the central station or exchange is the bat- 5 to t e terminals of which are connected, through Specification of Letters Patent.

Applioation'filed December 31,1906. Se

tery 22'"is'indue tively und 6 of'the line' relay, The

the side 1 of the line ci i c v connected-to groundthiioug the wire" ,t'o'the desired point foi t shatter inductively on the, co .nected in 'series with" A "designates one or the "sistance through whicl'it r i grounded side'of the cciid ti advantage, be. wound in the" 1 iephone susceptible to. adaptation to the present in-' resides 3 and rial n. 350,146;

of the cord circuit lead board jack 11. Bridged is the operators supervisory 1 Tip 2 connected in series with the'arrriatu visory relay 9. ii I equivalent mcansyar of the supervisory rel and, included in the it i circuit is the batter 's-2" connected to ground at r connectedwith the po 80 25 is non-inductively" amid venting fluttering of tli l 1 relay 19 is somewhat s w" in acting Th'esig nal lamp Z6 is connected across he ba i and 28, the' latter bein 1n 'sene' with relatively low resistan The sleeve spring 32 an of the cut-off relay, an being of sufiicient valueto keep Wn ii Bridged across the spr gs l e a tively high resistance rid I serves to actuate the mu 1' as to prevent ringing th nect the sleeve spring oftheiack subscribers line throii' li th the wire 1 to the tip spim 105 ferentiallywolind relay Qiand" stitute a unitary piece tif apparatiis ihi' ci'iveiiienceof installation. In practice; the resistance of the cut-off 110 relay may be from thirty to forty-five ohms, and the' shunt 39 thereof about half again as much. The coils of the supervisory relay 9 may be of a resistance varyin g from eighteen to thirty ohins, while their shunts are about one half greater. The rcsistance'ol the line rc-.

lay coils may be from one to two thousand ohms each.

When the subscriber A desires to communicate with another subscriber, he removes the receiver from the house telephone and the signal lamp 26 isthercby lighted, current flowing from the positive side of the linebattery 22 through coil 24 of the line relay 16,

armature 17, wire 2, through the transmitter and ro-.

ceiver'of the telephone, wire 1, armature 18, wire 21, coil 25, to ground 23. The coil 24 causes the armature 29 to close the signal lamp circuit so that current passes from the positive side of the battery 22 through line 27, lamp 26, line 28, armature 29 to the grounded side of the battery. Upon seeing the signal, the oper-- ator inserts the answering plug 10 of'the cord circuit into the jack 11 to ascertain the numberof the subscriber to be called. The cutoff relay is actuated only when the plug, is inserted and the receiver is off the hook of the 'subscribers telephone. Current continues to rnomentarily flow from the battery 22 through the wires 1 and 2, but, instead 'of passing to ground 22 through the arrhature 18, wire 21 and coil 25, the cur rent passes'th-rough the coil 30 of the cut-off relay, jack spring 31, tip ofthe answering plug, wire 3 of the cord circuit, to the grounded side of the exchange battery 5. This energizes the cut-off relay 19 so that its three armatures are thereby actuated and assume the position shown in Fig. 2. The signal lamp and line relay are thus cut out of the line circuit, and the cord and line circuits are connected together so that the exchange battery 5 supplies the talking current. After the exchange operator receives the number of the subscriber to be called, she inserts the call plug into the proper jack so that, the subscribers will be connected for conversation,

As soon as the conversation is overfthe subscriber A hangs upthe'receiver, the cut-off relay is lie-energized, and current flows from the exchange battery 5 through the coil 8, side 4 oi the cord circuit, plug and jack, and to ground through the wire 34, armature 35 and-resistance 36, the said armaturereturn ing to its normal position upon the cut-off relay being denergized The current passing through the coil 8 of the supervisory relay causes the armature 14 to be at trac'ted so that the supervisory lani'p circuit is completed and the lamp lighted to inform the operator'that' the subscribers have finished. i

When it is desired to call the subscriber at station A, the operator tests the circuit to see if the subscrib er to be called is connected with any other subscriber in the exchange, this being done by touching the tip of the f plug 10 to the test ring 33 in the usual manner.

- subscribers line is not busy, the plug 10 is inserted in the. inch 11 and aringing current sent through the cir- Sufiicient current passes from the sleeve spring If the 32 to the tip spring 31, or, in other words, from the side 4 to the-side? of the cord circuit, through the condenser 38 and inductive coil 37 on the cut ofi rela'y,,tlint the armature is actuated to be connected with the wire 2-of the line circuit, thereby forming a path-for the ringing current on one side of the line circuit; The

arrangement of the various apparatus and of the method of operation will be readily apparent to those skilled in the art to which the invention appcrta-ins. I have dc scribed the. principle operation of the invention, together with the apparatus which I now consider to be the best embodiment thereof, but I desire to have it understood that the apparatus. shown is merely illustrative, and that various changes may be made, when desired, as are within the scope of the claims.

What-is claimed is:-

1. In a telephone system. the combination with a central station, and n subscriber's station. of a cord circuit. a line 'circuit. a plug mm jack for connecting the circuits. a signal controlling relilyxircuit bridging the line circuit.

a cut-off relay for controlling the said relay circuit. and

a resistance and impedance circuit bridging the springs of the Jack and inductively related to the cut-off relay.

'2. In a telephouesystem. the combination with a central station. and subscriber's station, of a suitable cord circuit. a line circuit. a signal controlling relay connected acrossd'li'e line circuit. :1 cut-oil? relnyin the line circuit for controlling the said relay, a resistance and impedance containing co'nductouhridgiug the line circuit and inductively related to the cut-off relay and actuating the latter,

and a non-inductive resistance arranged in shunt relation with the cutoff relay. I p 4 3. In a-teleplione system. the combination of two wires -of a subscribeus line, a line relay connected across the wires, :1 signal controlling circuit associated wltlnihe relay, a source ofcncrgy included in the said circuits,

cutlpff relay having" its coil included in one of thesnid line wires and provided with armatures for connecting the line relay with the line wires. a conductor connected across the line wires and wound inductively on the cut-off relay,

and a high resistance shunt connected around the cut-olfrelny.

4. In a telephone system. the combination of two w'ires 'of a subscribers line. a double wound relay of high re slstance connected across the line wires. :3 hatt'ery connected. with the line relay, :1 signal circuit connected witl.i

the battery and controlled by the line relay. :1 cut-ulf relay having its coil connected with one of the lini. wires. :1 jack having its tip spring connected with the line wire containing the cul-ofi relay and its sleeve spring connected with the other line wire. a resistance containing: conductor connected \vlfh the sleeve spring and to ground and including nu armature of the cut-off relay. inst llllll'lllle connected with the said groundedconductor, a resistance containing conductor bridged across the Jacksprings nnd inductively related to the cut-off relay. and ii non-indi'ictive resistance arranged in shunt relation to the cut-olf relay.

In testimony that I claim tlw'forcgolng: as my own. I have hereto nlfixcd by. signature in llie presence of two witnesses. i EDWIN HUWl-lis' lll-LU-nltli. \Yltncsses: i

.l. B. 'KuLLl-zr. Jonx ALBERT. 

